fn main() {
    var m = {'a': 1, 'b': 2, 'c': 3}

    println('a =', m['a'])

    m['b'] = m['c']
    m['c'] =  33

    println(m['b'], m['c'])

    println(m.len())

    m.del('b')

    println(m.len())

    assert(m.contains('akb48') == false)
    assert(m.contains('b') == false)
    assert(m.contains('a') == true)

    m[''] = 110
    println(m[''])

    var b = m['b']
    println(b)
}
